NO. 2 A MIOCENE LONG-BEAKED PORPOISE KELLOGG 9 



narrower at the level of the supraorhital processes than that of 

 Eurhinodelphis bossi ' from the Upper Miocene Calvert formation 

 of Maryland, and the construction of the vertex is quite different. 

 In E. bossi, w^hich is approximately the same size as A. joaquinensis, 

 the nasal bones are quite small, the area of both nasals being some- 

 what less than the exposed portions of the combined frontals on the 

 vertex, and the thin outer border of the maxillary at the base of the 

 rostrum is bent upward. 



The genus Eurhinodelphis is not known to occur in Lower Mio- 

 cene deposits. There are, however, three related genera that are 

 characteristic of this geological stage. The long-beaked porpoise, 

 Ziphiodelphis abeli^ from the Lower Miocene Langhian sandstone 

 quarries of Bolzano, Italy, has the vertex similarly contracted in an 

 antero-posterior direction, the transverse diameter of the nasals being 

 almost twice the antero-posterior diameter, the exposed portion of 

 the combined frontals on the vertex is approximately equivalent in 

 area to that of the two nasals, and a small interparietal is present. 

 The supraoccipital shield is nearly vertical and flattened transversely, 

 the rather thin outer borders of the maxillaries are bent upward 

 at the base of the rostrum, and the hinder extremities of the pre- 

 maxillaries are not conspicuously thickened. The teeth, however, 

 have the roots markedly enlarged below the base of the enamel crown, 

 but are rapidly attenuated toward the extremity. This genus seems 

 to have its closest affinities with Eurhinodelphis. 



As regards Schizodelphis sulcatus from marine sediments belong- 

 ing to the Lower Miocene Langhian stage at Gauderndorf near Eg- 

 genburg, Austria,' and also from the Langhian sandstone quarries at 

 Belluno in Upper Italy,* the nasals are quite small, the frontals com- 



' Kellogg, R., On the occurrence of remains of fossil porpoises of the genus 

 Eurhinodelphis in North America. Proc. U. S. Nat. Mus., vol. 66, art. 26, 

 pp. 1-40, pis. 17, 1925. 



^ Dal Piaz, G., Sui vertebrati delle arenarie Mioceniche di Belluno. Atti 

 Accad. sci. veneto-trentino-istriana, Padova, CI. I, Anno V, pp. 13-16, figs. 5-7, 

 1908; Basani, F., and Alisuri, A. Sopra un Delfinorinco del calcare Miocenico 

 di Lecce (Ziphiodelphis abeli Dal Piaz). Mem. R. Accad. Lincei CI. sci. fis. 

 mat. e nat., Roma (5), vol. 9, fasc. 2, pp. 25-38, pi. i, fig. 6, 1912; Dal Piaz, G., 

 L'Istituto geologico dell' Universita di Padova nel 1922. Notizie Sommarie. 

 Mem. 1st. Geol. R. Univ. di Padova, vol. 6, p. 11, fig. 6, 1922. 



'Abel, O., Untersuchungen fiber fossilen Platanistiden des Wiener Beckens. 

 Denkschr. k. Akad. Wiss. math.-naturw. Kl., Wien, vol. 68, pp. 839-874, pis. 1-4, 

 1899. 



* Dal Piaz, G., Sugli avanzi di Cyrtodelphis culcatus dell'arenana di Belluno. 

 Pt. I. Palaeontographia Italica, Pisa, vol. 9, PP- 187-220, pis. 28-31, text figs. 16, 

 1903. 



